INT Interrupt Flags: O D I T S Z A P C
0 0
INT interrupt-num
Logic: PUSHF ; Push flags onto stack
TF 0 ; Clear Trap Flag
IF 0 ; Disable Interrupts
CALL FAR (INT*4) ; Call the interrupt handler
INT pushes the flags register, clears the Trap and Interrupt-enable
Flags, pushes CS and IP, then transfers control to the interrupt
handler specified by the interrupt-num. If the interrupt handler
returns using an IRET instruction, the original flags are restored.
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Operands Clocks Transfers Bytes Example
byte(word)
immed8 (type = 3) 52 5 1 INT 3
immed8 (type <> 3) 51 5 2 INT 21
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Notes: The flags are stored in the same format as that used
by the PUSHF instruction.
The address of the interrupt vector is determined by
multiplying the interrupt-num by 4. The first word
at the resulting address is loaded into IP, and the
second word into CS.
All interrupt-nums except type 3 generate a two-byte
opcode; type 3 generates a one-byte instruction
called the Breakpoint interrupt.
Seealso:
This page last updated on Fri Nov 30 10:49:50 MSK 2001
Copyright © 1992-2001, Vitaly Filatov, Moscow, Russia
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